Synthesis of Zinc Carbonate Hydroxide Nanoparticles Using Microemulsion Process

In order to control the particle size and morphology, zinc carbonate hydroxide Zn5(CO3)2(OH)6 nanoparticles have been synthesized using a reverse microemulsion technique. The pseudo-ternary phase diagrams of the two microemulsion systems, prepared using CTAB/1-butanol/n-octane/aqueous phase system with the aqueous phase comprised of either zinc nitrate (Zn(NO3)2) or sodium carbonate (Na2CO3), were experimentally constructed. The nanoparticles synthesized by mixing of the two emulsion systems were further characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The nanoparticles were further characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Several important experimental parameters have been investigated for the ability to control particle size and morphology as the function of water/surfactant molar ratio (ω), water/oil molar ratio (S) and the initial concentration of reactants in the aqueous phase. Results indicate that ω values have the ability to affect the particle size and levels of aggregation, while S values had no apparent effect. In addition, the initial concentration of reactants in the aqueous phase was considered to be an important parameter as raising its values from 0.1M to 0.5M produced an unknown phase of zinc carbonate, exhibiting larger particle size with a unique flake like morphology

Enhancement of tribological properties of mineral oil by addition of sorbitan monostearate and borate

Thesis (Doctoral)--Izmir Institute of Technology, Chemical Engineering, Izmir, 2010Includes bibliographical references (leaves: 225-235)Text in English; Abstract: Turkish and Englishxxviii, 248 leavesThe development of modern automobile and engine industries requires lubricants that can withstand high temperatures and pressures. Recent advances made in the chemistry provide the use of inorganic particles as lubricant additives. Therefore inorganic boron-based additives have been the focus of much attention, as they posses a good combination of properties, such as wear resistance, friction-reducing ability. In this study, the state of art in the field of inorganic particle, zinc borate synthesis and its employment in tribology were investigated. The synthesis of zinc borate was achieved not just by precipitation, but also production methods such as inverse emulsions. The products were characterized by SEM, FTIR, TGA, DSC, EDX. In lubrication part, the friction reducing and antiwear ability of the particles as an additive in the mineral oil was focused. Sorbitan monostearate was used to cover the surfaces of inorganic particles in order to provide better dispersion of additives in the oil. Friction and wear behavior of the lubricants were measured by four-ball wear test machine. The effects of dispersing agent, zinc borate type as well as surfactant concentration on the tribological properties of the lubricants were investigated. Sorbitan monostearate not only outperformed as a dispersing agent of inorganic particles, but also it proved to be an efficient antiwear agent. The lowest wear scar diameter was obtained by the lubricant containing zinc borate synthesized via coordination precipitation method. The addition of this sample with the surfactant in the oil reduced the wear scar diameter from 1.402 mm to 0.550 mm

Controlled Synthesis of Nanomaterials using Reverse Micelles

Monophasic nanosized oxides were synthesised mainly from metal oxalate nanorods obtainedusing the reverse micellar method. This paper focuses on the methodology to obtain importantmetal oxides like tin dioxide, cerium oxide (CeO2 ), zirconia, and zinc oxide. The effect of oxidationstate of the metal ion on the morphology of the oxalates was studied. Nanorods of zinc (II)oxalate (120 nm in dia and 600 nm in length) were obtained while spherical particles of size 4Œ6 nm were obtained for cerium (III) oxalate. The decomposition of these precursors at highertemperature led to the formation of their respective oxides. Mixture of nanorods and nanoparticles of CeO2 was obtained while 3Œ4 nm sized ZrO2 nanoparticles were obtained by thermaldecomposition of zirconium oxalate precursor. The dielectric constant and loss were highly stablewith frequency (at room temperature) for both ceria and zirconia nanoparticles.  ZnO nanoparticles(55 nm sized) were obtained by the decomposition of zinc oxalate nanorods. Three peaks corresponding to free excitonic emission, free-to-bound, and donor-acceptor transitions were observed in the photolumine scence studies at 20 K for ZnO nanoparticles.Defence Science Journal, 2008, 58(4), pp.531-544, DOI:http://dx.doi.org/10.14429/dsj.58.167

Nanocomposite formulations for enhanced oil recovery (EOR)

The energy crisis faced in the past few years by the decreasing oil prices and the restriction of recovering oil by conventional methods has developed a huge barrier. This barrier is the difficulty to recover oil by unconventional methods because of their high operation cost and the high cost of the materials required to achieve a successful operation. The main scope of this work is to investigate several zinc oxide nanocomposite formulations and their effect on enhancing oil recovery by surfactant polymer flooding methods compared to conventional surfactant polymer flooding. Since the investigation showed a good impact of ZnO nanomaterial on natural polymers but not the same on synthetic polymers and due to limited resources and time; it was decided to work on ZnO NPs/surfactant (Zinc Oxide Nanoparticles/ Surfactant) flooding instead during the core flooding phase. The work in this thesis is divided into three main phases; synthesis and characterization of nanomaterials, chemicals testing (including surfactants and polymers), and core flooding application. It was possible to fabricate reproduciable ZnO and TiO2 nanostructures. Upon characterization, preferential ZnO nanostructures were selected to undergo further testing. In the second phase, natural and synthetic polymers were tested to evaluate the impact of ZnO on their degradation and viscoelastic properties. The results showed a positive impact on natural polymers but a negative one on synthetic polymers. In addition, since the ZnO nanoparticles is flooded in the form of suspension; it was crucial to test ZnO suspension stability in various surfactants as well as the effect of ZnO NPs on interfacial tension. The results showed that ZnO NPs/SDS (Zinc oxide nanoparticles/ Sodium Dodecyl Sulphate) is the most stable suspension at ZnO concentration of 0.05 weight percent giving the most optimum reduced interfacial tension. Finally, upon the excution of core flooding experiments, the results showed an incremental oil recovery of 8% compared to conventional surfactant flooding

Synthesis of microporous silica nanoparticles to study water phase transitions by vibrational spectroscopy

Silica can take many forms, and its interaction with water can change dramatically at the interface. Silica based systems offer a rich tapestry to probe the confinement of water as size and volume can be controlled by various templating strategies and synthetic procedures. To this end, microporous silica nanoparticles have been developed by a reverse microemulsion method utilizing zinc nanoclusters encapsulated in hydroxyl-terminated polyamidoamine (PAMAM-OH) dendrimers as a soft template. These nanoparticles were made tunable within the outer diameter range of 20-50 nm with a core mesopore of 2-15 nm. Synthesized nanoparticles were used to study the effects of surface area and microporous volumes on the vibrational spectroscopy of water. These spectra reveal contributions from bulk interfacial/interparticle water, ice-like surface water, liquid-like water, and hydrated silica surfaces suggesting that microporous silica nanoparticles allow a way to probe silica water interactions at the molecular scale

Three-dimensional ZnO hierarchical nanostructures: Solution phase synthesis and applications

Zinc oxide (ZnO) nanostructures have been studied extensively in the past 20 years due to their novel electronic, photonic, mechanical and electrochemical properties. Recently, more attention has been paid to assemble nanoscale building blocks into three-dimensional (3D) complex hierarchical structures, which not only inherit the excellent properties of the single building blocks but also provide potential applications in the bottom-up fabrication of functional devices. This review article focuses on 3D ZnO hierarchical nanostructures, and summarizes major advances in the solution phase synthesis, applications in environment, and electrical/electrochemical devices. We present the principles and growth mechanisms of ZnO nanostructures via different solution methods, with an emphasis on rational control of the morphology and assembly. We then discuss the applications of 3D ZnO hierarchical nanostructures in photocatalysis, field emission, electrochemical sensor, and lithium ion batteries. Throughout the discussion, the relationship between the device performance and the microstructures of 3D ZnO hierarchical nanostructures will be highlighted. This review concludes with a personal perspective on the current challenges and future research

Preparation of Nanoparticles

Innovative developments of science and engineering have progressed very fast toward the synthesis of nanomaterials to achieve unique properties that are not the same as the properties of the bulk materials. The particle reveals interesting properties at the dimension below 100 nm, mostly from two physical effects. The two physical effects are the quantization of electronic states apparent leading to very sensitive size-dependent effects such as optical and magnetic properties and the high surface-to-volume ratio modifies the thermal, mechanical, and chemical properties of materials. The nanoparticles’ unique physical and chemical properties render them most appropriate for a number of specialist applications

Microemulsions as Nanotemplates: A Soft and Versatile Approach

Template efficacy of microemulsions in generating nanoparticles has garnered considerable attention in the world of colloidal science. A microemulsion is an optically isotropic and thermodynamically stable colloidal dispersion, which possess spherical droplets (either of W/O or O/W) of the size <50 nm. In microemulsions, the spontaneous formation of domains of nanometric dimensions significantly facilitates their exploitation as potential nanoreactors for the production of stable nanoparticles (due to their cost-effectiveness and ease of preparation). The present chapter provides an overview of microemulsions as efficient nanotemplates, with a detailed account of plausible nanomaterials, i.e., metallic nanoparticles, quantum dots, polymeric nanoparticles, mesoporous silica nanoparticles, solid lipid nanoparticles, nanostructured lipid carriers, etc. Based on the high surface area, good crystallinity, controllable particle size, outstanding catalytic, and magnetic properties, the exploitation of nanoparticles as efficient catalysts and drug delivery modules has also been highlighted